While appropriate for many applications, conventional microwave susceptors generally have just one temperature output. In addition to having no temperature regulation, conventional susceptors often do not generate enough heat to achieve adequate browning and crisping, or in some instances, cook food unevenly, burning the food in some areas while under cooking the food in others. The following is a comparison to the three known susceptor types: 1) fully metallized film; 2) demetallized film; and 3) printed susceptors.
Fully metallized thin film susceptors have one heat output across the entire surface. This lack of control results in overcooking certain areas of the food (such as the edge of a pizza) while undercooking the center. Additionally, the amount of heat generated is not sufficient to compare favorably with traditional cooking methods such as baking.
Demetallized susceptors address the lack of control by reducing heat in areas that tend to overcook. While this can be effective, the result is slower preparation time and improper browning. Area heat is reduced by removing metal (demetallizing) in the areas where the food is being overcooked, resulting in less browning. While demetallization can provide balanced cooking results for some foods, the results still fall short of traditional cooking methods because thin film metallized susceptors do not provide the heat required to properly brown many foods.
The third style of susceptor is printed. While printed susceptors have been used experimentally, they have not enjoyed much commercial use. The reason for this is that known printed susceptors generally lack the temperature regulation to assure that the package does not “runaway heat”, which can result in the package catching fire. Printed susceptors lack the natural “thermostat” that is inherent in film susceptors. That is, when a metallized film reaches a certain temperature it naturally cracks and reduces its heat output. In contrast, printed susceptors absorb energy as long as microwave energy is applied to it. The result can be package ignition.